The present invention refers to a device intended for the continuous lowering of bulk products along substantially vertical tracks.
The invention finds application in any case of continuous lowering of bulk products when it is important to avoid shock or chrushing; this is the case, for example, in the loading or unloading of ore or coalships in order to avoid screened pieces of ore, coal or coke being reduced to fines by too great free falls.
At present various types of inclined conveyor are employed, belt, straight or spiral toboggan or fixed pipe.
Belt conveyors are heavy and bulky; in loading ports, for example, these conveyors occupy considerable space obstructing activities on the quay. Spiral toboggans have reduced bulk but the slope of the spiral must take into account the nature of the product conveyed in order to avoid either too rapid descent or clogging, which limits their employment. Further, they are subjected to rapid wear and high heating due to friction. Fixed pipes, substantially vertical, present the same disadvantages as toboggans (wear, free fall, or void-effect and clogging).
The present invention applies a rational solution to these problems.
It is applied to a device fed with bulk material at a fixed or variable upper level and having a lower discharged conveyor.
In accordance with the invention there is provided a device for continuously lowering a supply of bulk material from an upper level to a discharge conveyor at a lower level, the device comprising an endless conveyor having a rectilinear descending portion, the conveyor forming in said portion an open channel having rigid sides, means of closure of this channel in the descending portion lying between the upper level and the lower discharge level defining with the conveyor between the two levels a closed chimney having rigid descending walls, means of regulation of the speed of the vertical conveyor as a function of the material feed flow in order to keep the upper level of material in the chimney at a constant level, and means of regulating the speed of the discharge conveyor at a constant ratio to that of the vertical conveyor, this ratio being determined so that the flow from the discharge conveyor is equal to that of the vertical conveyor with its chimney filled with material.